Update via heigl and PerezHilton [ugh]:"Heidi and Spencer got their hands on an old demo recording of Britney's that never made it onto any of her albums," an insider reveals exclusively to PerezHilton.com. "They've been working with a lot of producers on Heidi's new album and one of them gave them the track. They decided to turn it into a duet instead of having Heidi re-record the song with just her vocals because they knew they'd get more press this way.

"Heidi and Spencer got their hands on an old demo recording of Britney's that never made it onto any of her albums," an insider reveals exclusively to PerezHilton.com. "They've been working with a lot of producers on Heidi's new album and one of them gave them the track. They decided to turn it into a duet instead of having Heidi re-record the song with just her vocals because they knew they'd get more press this way."